package com.online.web.shiro.action.shiro;

import java.awt.image.BufferedImage;

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import com.google.code.kaptcha.Constants;
import com.google.code.kaptcha.Producer;

/**
 * 使用 Captcha 生成验证码，相关配置在applicationContext.xml中。<br />
 * 项目网址：<a href="http://code.google.com/p/kaptcha">http://code.google.com/p/kaptcha</a>
 */
@Controller
public class CaptchaImageCreateAction {

    @Autowired
    private Producer captchaProducer;

    /**生成验证码*/
    @RequestMapping("/resource/captcha-image")
    public void captcha(HttpServletRequest request, HttpServletResponse response) throws Exception {
        createCaptcha(request, response);
    }

    /**
     * 验证用户输入的验证码
     * @param captcha 用户输入的验证码
     */
    public static boolean validCaptcha(HttpServletRequest request, String captcha) {
        Object sessionCaptcha = request.getSession().getAttribute(Constants.KAPTCHA_SESSION_KEY);
        if (sessionCaptcha == null || StringUtils.isBlank(sessionCaptcha.toString())) {
            return false;
        }
        return StringUtils.equals(captcha, sessionCaptcha.toString());
    }

    private void createCaptcha(HttpServletRequest request,
                               HttpServletResponse response) throws Exception {
        // Set to expire far in the past.
        response.setDateHeader("Expires", 0);
        // Set standard HTTP/1.1 no-cache headers.
        response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
        // Set IE extended HTTP/1.1 no-cache headers (use addHeader).
        response.addHeader("Cache-Control", "post-check=0, pre-check=0");
        // Set standard HTTP/1.0 no-cache header.
        response.setHeader("Pragma", "no-cache");

        // return a jpeg
        response.setContentType("image/jpeg");

        // create the text for the image
        String capText = captchaProducer.createText();

        // store the text in the session
        request.getSession().setAttribute(Constants.KAPTCHA_SESSION_KEY, capText);

        // create the image with the text
        BufferedImage bi = captchaProducer.createImage(capText);

        ServletOutputStream out = response.getOutputStream();

        // write the data out
        ImageIO.write(bi, "jpg", out);
        try {
            out.flush();
        } finally {
            out.close();
        }
    }
}
